Arc-lamp.



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P.. mM HA L CC R WA APIYJIOATION FILED JUNE 12, 1901.

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Inventor WaHSe' CFh.

by Atty;

UNITED STATES Patented September 15, 1903.

PATENT OFFICE.

VALTER C. FISH, OF LYNN, MASSACHUSETTS, ASSIGNOR TOGENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ARC-LAM P.

SPECIFICATION forming part of Letters Patent No. 738,896, dated September 15, 1903. Application filed lune 12,1901. Serial No. 64|205. (No model.)

To @ZIM/hom t may concern:

Be it known that I, WALTER C. FISH, a citi-v zen of the United States, residing at Lynn, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Arc-Lamps, of which the following is a specification.

My present invention relates to means for securing stability of operation of arc-lamps, whereby the use of a steadying resistance in series with the lamp may be either wholly discontinued or the amount of resistance largely reduced, thereby increasing the percentage of useful energy expended at the arc, and so improving the efficiency of the lamp as a whole.

In carrying my invention into practice I provide an arrangement whereby the arc-regulating mechanism responds readily to small variations of current, thereby securing through the regulation of the arc itself a steadiness of current heretofore generally obtained by the use of a steadying resistance, the employment of which is objectionable on account of the energy consumption therein.

The novel features which constitute my invention I have set forth more particularlyin the claims appended hereto. For a detailed description of these novel features and of other elements going to make up alamp constructed in accordance with my invention reference is to be had to the following description, taken in connection with the accompanying drawings, in whichy Figure l represents one embodiment of my invention, and Fig. 2 a modified arrangement of circuits.

The lamp shown in Fig. l includes two sets of magnets, one set being arranged to act diiferentially with respect to the other and both sets being controlled by current iowing through the arc. One set of magnets (indicated at 1) acts to produce a separation of the carbon or other electrodes 2 3, and I may therefore term the same main magnets or magnet-coils. The other set of magnets or magnet-coils is indicated at 4 and is arranged to act in opposition to the first set of magnets, for which reason I may term the same dierential magnets. The windings of these two sets of magnets 1 and 4 are shown ,wardly-extending rod 9.

as connected in series with each other and with the electrodes 2 and 3 in a manner readily understood.

The main magnet coils l are arranged in operative relation to a U-shaped core 5, fixed to a tube 6, which supports aclutch 7, acting on the upper or movable carbon 2.

In a somewhat similar manner the magnetcoils 4 are arranged in operative relation to a U -shaped magnet-core 8, secured to a down- The rod 9, which for the sake of lightness may be hollow, is connected to the tube 6 through a spring or springs l0. Various types of springs may be employed. In the present instance I have shown two mechanically connected bowsprings as suitable for the purpose, one of the springs being fixed to the rod or tube 9 and the other to the rod 6, the opposingl ends of the springs being riveted or otherwise secured together, as shown at 11 and l2. Interposed between the windings of the magnet 4 and the core S are placed heavy short circuits 1-3 14, consisting in the present casel of thick tubes of copper or other good conducting material. The object of these short circuits is to shut off from the core 8 the effect of sudden variations of current in the windings 4, thereby rendering lthe diferentialmagnet system slow to respond to variations of current in the lamp.

To restrain too violent motion of the arcregulating mechanism, I may employa dashpot consisting of a cylinder 15, carried by upwardly-extending arms lli-and 17, fixed, as shown, to the U-shaped core 8, and a cylinder, the lower end of which, 18, is carried by a yoke-piece 19, fastened to some iiXed portion of the lamp-in the present instance to the magnets 4.

In order to make clear the mode of operation of the lamp, let it be supposed that a sudden fluctuation of current-as, for example, a sudden increase of current-takes place, due to any cause. The main magnet l then acts to draw up its core 5,thereby producing a greater separation of the carbons 2 3. At the same time current increases in the same proportion through the winding of the dierential magnet 4. Owing, however, to the screening ef- IOO fect of the short circuits 13 the effect of this uctuation of current is notimmediately felt by the core of the differential magnet, due to which fact the resultant action of the main and differential magnets is for a moment increased by a considerably greater amount than that which would result with a slow increase of current to the same value as that momentarily existing in the magnet-coils 1 and 4. The sudden impulse thus exerted on the arc regulating mechanism thereupon promptly separates the electrode and brings the current back to its normal value, the action being so prompt as to prevent the fluctuation of current from reaching any considerable proportions, such as would endanger the stability of the lamp and set the parts to pumping or hunting.

In case a decrease of current momentarily takes place the magnetornotive force of the main coil 1 decreases correspondingly, while that of the differential coil 4lags behind, being retarded in this case by the induced current set up in the short circuits 13 and 14. The resultant differential action of the coils 1 and 4 is therefore decreased in a greater proportion than the decrease of current, thereby permitting a more prompt approach of the electrodes 2 3, and so preventing'a violent fluctuation of current by checking the fluctuation in its incipiency. This action is hastened through the instrumentality of the energy stored up in the springs 10. Thus when the lifting power of the magnets 1 decreases, due to decrease in current, the springs 10, which are under compression, add their tension to that of gravity, thus obtaining increased acceleration of the carbon-holding mechanism in its downward movement. The tube or rod 9, attached to the magnet-core 8, receives the reactive force of the springs 10 and adjusts its position as the arc-controlling mechanism gradually moves downward as the upper carbon burns away, thereby maintaining the springs 10 under substantially uniform tension whether the clutch 7 is at the feeding-point or is at the limit of its upward movement.

Fig. 2 shows au arrangement of circuits whereby the retardation or lagging Aof the magnetic pull of the differential coils may be increased still more than is obtainable by the use merely of the short circuits 13 and 14.

' (Shown in Fig. 1.) In Fig. 2 the main magnet-coils are indicated in diagram at 2O and the dierential coils at 21, the latter coils being shown as wound about short circuits 22 and 23 of the same character as in Fig. 1. The dierential magnet-coils 21, however, instead of being placed directly in series with the main magnet-coils 20, as in Fig. 1, are placed in one of two branch circuits which carry the current flowing through the magnet-coils 20. The branch containing the coil 21 includes an inductance-coil 24 of considerable self-induction. The other branch contains a non-inductive resistance 25 and is shunted about the branch including the inductance-coil 24 and the windings 21, as shown. Current is supplied by mains, (indicated conventionally at 26 and 27,) and after vpassing through the parts already described flows through the arc 28 and back to the supply-mains, as indicated. In the arrangement thus described it will be evident that in the event of a fluctuation of current in the arc there will be a resulting subdivision of current in lthe two branch circuits mentioned. The non-inductive branch 25, being of very low-time constant, oiers little if any retardation to the uctuation of current in the arc. Current in the other branch circuit, which has a high-time constant, due to the presence therein of the inductance-coil 24, is prevented from rising or falling quickly due to the choking action of the inductance-coil. The response of current in this branch circuit being therefore lagged behind that in the main circuit including the arc causes the magnetic effect of the differential winding 21 to lag correspondingly. This effect is intensified still more by the presence of the secondary or short circuits 22 and 23 in a manner well understood in the art. Since the dierential effeet of the magnet or coils 21 is by the means described lagged orretarded behind that of the main coils 21, it will be evident that the resultant effect of the magnet system as a whole is rendered more powerful for temporary iuctnations of current than is the case after the cur- IOC rent becomes steady. The result is that the tendency to variation of current in the arc is powerfully checked at its inception and the progress offurther variation destroyed. The operation of the lamp is thus rendered stable and corresponding advantages secured, as above indicated.

' What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. The combination ofamain magn-et-winding, an opposing winding in circuit With the main winding, a short-circuited conductor in operative relation to said opposing winding, and a clutch mechanism in operative relation to said windings.

2. In an electric-arc lamp, the combination of a plurality of controlling-magnets connected in series, and means for retarding the magnetic effect of one of said magnets.

3. In an electric-arc lamp, the combination of a main magnet tending to strike the arc, an opposing magnet, and means for causing the current in the winding of the opposing magnet to lag behind or be retarded with respect to the current owing in the main magnet.

4. In an electric-arc lamp, the combination of a magnet-winding, an inductance-coil in shunt with said winding, and a non-inductive shunt across said inductance-coil and winding.

5. In an electric-arc lamp, the combination of means acting to separate the electrodes of the lamp, electrical means for opposing such IIO separation, and means for rendering the action of such opposing means more sluggish than that acting to separate the electrodes.

6. The combination of a main armature, clutch mechanism carried thereby, an armature acting in opposition to the main armature, and a spring connecting said armatures.

7. The combination of a main armature, clutch mechanism carried thereby, an opposing or differential armature, and a compression'spring connecting said armatures.

8. In an electric-arc lamp, the combination of an arc-striking magnet, a mechanism controlled thereby, a spring for opposing motion of said mechanism, and an electrically-actuated movable device for receiving the reactive eect of said spring.

9. In an electric-arc lamp, the combination ofamagnet tending to oppose the lengthening of the arc, and means for causing the magnetic effect of said magnet to vary slower than the variation of current through the arc. 10. In an electric-arc lamp, the combination of a main coil and a differential coil, both connected so as to carry current iiowing through the arc, and a short-circuited conductor for causing the magnetomotive force due to the current in the differential-coil to Vary at a rate slower than the rate of variation of current in the main coil.

In witness whereof I have hereunto set my hand this 7th day of June, 1901.

WALTER' C. FISH. Witnesses:

DUGALD MOK. MoKILLoP, JOHN A. McMANUs. 

